A vehicle communication bus allows for various control modules within a vehicle to communicate with one another. For example, a controller area network (“CAN”) network is a vehicle bus standard that allows control modules to communicate with one other within a vehicle without a host computer.
As a result, if a specific control module is not connected to the vehicle communication bus (sometimes referred to as a non-bussed control module), then the non-bussed control module is unable to receive instructions or commands from an external source (e.g., to initiate a self-diagnostic mode). Thus, in one approach to initiate a self-diagnostic mode, the non-bussed control module is removed from the vehicle in order to receive instructions or commands, which may be time-consuming and inconvenient. In another approach, an input/output (I/O) line may be attached to the non-bussed control module, where commands are sent through the I/O line to initiate the self-diagnostic mode. In yet another approach, a jumper harness may be connected from a laptop or other portable computer to the non-bussed control module to send commands and initiate the self-diagnostic mode. Alternatively, in another embodiment, a light sensor may be added to the non-bussed control module to receive and read light pulses. In yet another embodiment, a radio frequency (“RF”) receiver may be added to the non-bussed control module for receiving RF commands to initiate the self-diagnostic mode. However, each of these approaches generally add cost and complexity to the non-bussed control module. Accordingly, it is desirable to provide a cost-effective, relatively simple approach for allowing a control module that is not connected to a vehicle communication bus to receive instructions or commands.